Scientists have discovered dunes on Pluto, and say they are likely to have been formed of methane ice grains released into its rarefied atmosphere.
Writing in Science, an international team of geographers, physicists and planetary scientists have analysed detailed images of the dwarf planet’s surface, captured in July 2015 by NASA’s New Horizons spacecraft.
Those images showed that on the boundary of the Sputnik Planitia ice plain, and pushed up against a major mountain range, there is a series of dunes spread across an area less than 75km across.
Following spatial analysis of the dunes and nearby wind streaks on the planet’s surface, as well as spectral and numerical modelling, scientists believe that sublimation (which converts solid nitrogen directly into a gas) results in sand-sized grains of methane being released into the environment.
These are then transported by Pluto’s moderate winds (which can reach between 30 and 40 kmh), with the border of the ice plain and mountain range providing the perfect location for such regular surface formations to appear.
The scientists also believe the undisturbed morphology of the dunes and their relationship with the underlying glacial ice suggests the features are likely to have been formed within the last 500,000 years, and possibly much more recently.
The research was led by scientists from the University of Plymouth (UK), University of Cologne (Germany) and Brigham Young University (USA).